I want to pull the brake drums off to check the rear brakes on my '75 GMC pickup with a 14 bolt full floating rear axle.

The GM repair manual just says to disconnect the emergency brake cable and remove the wheels, and the drums should just pull off. Is it really that easy on this big FF axle? The manual also says it should have a standard star wheel adjuster that can be backed off manually to get clearance from the shoes to the drum.

Also, do you have any words of wisdom or warnings on replacing the brake shoes? I have the HD brakes on my K25, so it has the large drums, which should have the wide shoes and 13" diameter drum. Other than size, it looks like they are the same as any other drum brake setup.

This is the Transmission/Rearend forum.......brake questions should go in the Brake forum. But yes you manual is telling you right. Only take one side at a time down...that way you can go look at the other side for referance as you put it back together. Go get you a set of heavy duty brake spring pliers as you are going to need them. They make it a lot easier and safer.

I went back to the manual, and realized that your description seems to match the GM manual for the 14 bolt.

The directions for removing the drum on the 14 bolt refer back to the directions for removing the axle first. It looks like its quite a bit more complicated than simply pulling the drum. The only holdup I have today is that I don't have the bearing wrench.

Is the bearing wrench for the 14 bolt FF the same size as the one for the Dana 44 in the front? I've seen several of these wrenches at the store, but never took a close look to see how many sizes there are.

No...it is not the same size as the front D44. It is the same size as the D60 (k30) front end spindle nut spanner socket. Kragen MIGHT have them. Autozone will not have it. Your best bet is NAPA or some other quality parts store. The torque spec is HUGE so there is no way to do it without the proper socket.

To make it easier to remove I use a long extension and put a jack stand under it to be sure I don't lever the socket out while trying to break it loose.

If the drums are worn you should look into a disc brake swap because those rotors are about $130 each

My disc brake swap
d44 front calipers $40
Brake pads $40
Brackets $65
Rotors (77 K20) $70
The rest was stuff I had laying around. If you want an e-brake it will be more money...but I have a driveshaft mounted e-brake.

None that I know of. I have one bolted to the back of my transfer case made by High Angle Driveline http://highangledriveline.com/e_brake.html It holds much much better then my factory 12-bolt drums did because it works through my 4.56:1 gear reduction. I think some Land Rovers came with a drum on the t-case output for an e-brake.

thw 14 FF brakes were all 13"
were 2.5" wide and some 3.5" wide depending on the model and GVRW rating of the truck

to pull the drums you hvae to first unbolt the axle shafts and pull them

then inside there are two large nuts and washer tang lock plates, these hold the bearings and hubs on

its an oily greasy job, you wil lose some gear oil so you will have to top it off after reassembly

your gm repair manual is obviously not for the 3/4 and 1 ton trucks before 1981

the drum brake setup on these is conventional with single adjuster assembly at the bottom yes, nothing different, just larger parts is all

if you need any more info or want to see pics of me taking the drum off the 3/4 ton 14 FF that i have outside then lemme know

as i have to take it apart to put new wheel seals in it anyways

you can tell a 3/4 ton one from a 1 ton one by the length of the hub, the 1 ton hub sticks out alot further than the 3/4 ton one like i have in my pic above, and also the 1 ton drums are wider

the driveshaft brake drums were only on the medium and heavy duty trucks(C-40 and up/ 1.5 ton and up) and they had no park in the tranny

if you need to know anything about GM trucks from '67-87 then jut let me know, they are my specialty and have been for over a decade i have owned billions of them, all kinds of different models and sizes, panels, burbs, blazers, pickups, C&C's, G-10 and G-20 vans, etc

good luck

Quote:

Originally Posted by 75gmck25

I want to pull the brake drums off to check the rear brakes on my '75 GMC pickup with a 14 bolt full floating rear axle.

The GM repair manual just says to disconnect the emergency brake cable and remove the wheels, and the drums should just pull off. Is it really that easy on this big FF axle? The manual also says it should have a standard star wheel adjuster that can be backed off manually to get clearance from the shoes to the drum.

Also, do you have any words of wisdom or warnings on replacing the brake shoes? I have the HD brakes on my K25, so it has the large drums, which should have the wide shoes and 13" diameter drum. Other than size, it looks like they are the same as any other drum brake setup.

Thanks for the additional info on the brakes. The OEM GM manual I have does cover all the axles and in most cases has good directions However, it covers all the '74 and '75 light duty models (pickups, subs, step-vans, etc) and it takes careful reading to make sure I'm looking at the right instructions.

I'm going to wait until I have a full weekend available to pull the rear brakes apart. I looked through the inspection ports and it doesn't look like the linings are anywhere near metal on metal. I haven't had rear brakes apart since I got the truck from my father-in-law about four years ago, and its one of the last items I need to go through.

My father-in-law used the truck on the farm and usually did a good job on standard maintenanace (like brakes). However, it took me nearly two years to get through all the body repairs and fixes for what he considered non-essential. For example, when I got it the only items on the dash/interior that worked were the mechanical oil pressure gauge and an add-on temp gauge. There were blown fuses and missing grounds that screwed up everything else on the dash.

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